00.斐波那契数列第n项

# 斐波那契数列第n项

# 1 1 2 3 5 8

def fib(n):

    if n <= 2:

        return 1

    else:

        return fib(n-2)+fib(n-1)

def fib2(n):

    if n < 3:

        return 1

    f1 = f2 = 1

    for k in range(1, n-1):

        f1, f2 = f2, f2+f1

    return f2

if __name__ == '__main__':

    # 1 1 2 3 5 8 13

    print(fib(6))  #

    print(fib2(6))  #